Shanghai is the best city to prevent the spread of COVID-19 infection in China. Since February 20, 2020, Shanghai has experienced five waves of COVID-19. Out of a total of 388 patients with COVID-19 symptoms, 381 were cured and seven died. Medical staff achieved zero infection. This paper summarizes, analyzes and simulates COVID-19 epidemics in Shanghai. The simulation results show that for five waves of epidemics, after reaching the infection turning point, the blocking rate of symptomatic infection is over 99%. The administration needs to maintain the prevention and control implemented 7 days after reaching the infection turning point until the new infection goes away.

Background: The recent COVID-19 epidemic in mainland China is an important issue for studying the prevention and disease control measures and the spread of the COVID-19 epidemic. Following our previous study for the mainland China epidemic during December 6 2021 to 30 April 2021, this paper studies and compares the the mainland China epidemic during December 6 2021 to December 6, 2022. Methods: Using differential equations and real word data (both domestic and foreign input infected individuals) modelings and simulates COVID-19 epidemic in mainland China during May 1 2021 to December 6 2022, estimates the transmission rates, the recovery rates, and the blocking rates to the symptomatic and the asymptomatic infections. Results: The simulation results were in good agreement with the real word data. (1) The average input transmission rate of the foreign input symptomatic infection individuals was much lower than the average transmission rate of the symptomatic infection causing by the mainland symptomatic individuals. (2) The average input transmission rate of the foreign input asymptomatic infection individuals was was much lower than the average transmission rate of the asymptomatic infection causing by the mainland symptomatic individuals (3) The average recovery rates of the foreign input COVID-19 symptomatic and asymptomatic infected individuals were much higher than the average recovery rates of the mainland COVID-19 symptomatic and asymptomatic infected ndividuals, respectively. For the mainland epidemic simulations: (1) If kept the transmission rates, the recovery rates, the death rate and the blocking rates on day 181 (June 30, 2022), the numbers of the current symptomatic and asymptomatic individuals would reduce to about one on day 277 (October 4, 2022). (2) If kept the transmission rates, the recovery rates, the death rate and the blocking rates on day 340 (December 6, 2022) until day 377 (January 16, 2023), the numbers of the current symptomatic and the asymptomatic infected individuals would increase to 38896 and 230924, respectively, the cumulative death individuals would increase from 599 to 615, respectively. (3) If kept the transmission rates, the recovery rates on day 340, but decreased the blocking rates to 30% and select the death rate to equal to the average death rate during days 104-150, then the simulation showed that on day 377, the numbers of current symptomatic and the asymptomatic infected individuals would increase to about 33 723 8057 and 501 626 885, espectively, and the cumulative death individuals would reach about 1 012 543. For the foreign input epidemic simulations: (1) If kept the transmission rates, the recovery rates, and the blocking rates day 242 (August 30, 2022), until day 340, the numbers of the current symptomatic and the asymptomatic infected individuals would decrease to 13 and 430, respectively. (2) If kept the transmission rates, the recovery rates, the death rate and the blocking rates on day 340 until day 377 (January 16,2023), the numbers of the current symptomatic and the asymptomatic infected individuals would decrease and increase to 185 and 1935,respectively. (3) Recommendations on COVID-19 epidemic base on WHO's technic guidelines and HBV Infection in Chimpanzees are provided. Conclusions: (1) For the mainland individuals' epidemic, keeping the blocking rates of over 86% and 93% to the symptomatic and asymptomatic infections , and the recovery rates of over 0.119 and 0.112 to the symptomatic and asymptomatic individuals may make the numbers of the current symptomatic and asymptomatic infected individuals to decrease to very low levels in three months. (2) For the foreign input individuals' epidemic, keeping the transmission rates of under 0.07 to the symptomatic and asymptomatic infections , and the recovery rates of over 0.125 and 0.099 to the symptomatic and asymptomatic individuals may make the numbers of the current symptomatic and asymptomatic infected individuals to decrease to very low levels in four months. (3) After December 6, 2022, decreasing the blocking rates of under 30% to the symptomatic and asymptomatic infections may cause over 800 millions individuals' COVID-19 infections and over 10 millions COVID-19 infected individuals' death. (4) It is necessary that administrations implement strict prevent and control strategies to prevent the spread of new COVID-19 variants.

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